Abstract: Disclosed is a system and method for remote detection and identification of unknown chemical species in gaseous, aerosol, and liquid states. A pulsed infrared laser is directed at an unknown chemical mass which absorbs energy at the laser wavelength. Due to molecular energy transfer processes, the absorbed laser energy can be re-emitted in one or more wavelength regions nonresonant with the laser wavelength. The re-emitted energy is detected for a period of time which is comparable to or less than the characteristic time for the absorbed radiative energy to be dissipated as heat. The nonresonant infrared emission spectrum of the unknown chemical species is detected with several infrared detectors. The identity of the unknown species, as well as its range and concentration, may be established by comparison of its spectrum to that for known species.